Tuning coil



Nov. 12, 1929. J. J. STARR Y ,735,0 0

TUNING COIL Filed A ril 29. 1926 4 Sheets-Sheet 1 j-Tcfl;

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ATTORNEYS Nov. 12, 1929. R. J. J. STARRJ 1,735,020

I TUNING COIL Filed April 29. 1926 4 Sheets-Sheet 4 111111111lilkilllllllil)Il)/llllln WITNESSES INVENTOR R al/59mm ATTORNEYS Patented Nov. 12, 1929 UNITED STATES PATENT OFFICE.

TUNING COIL Application filed April 29, 1926, Serial No. 105,587, and in Ganada March 29, 1926.

This invention relates to a tuning coil for radio.

An object of the invention is to provide simple and efficient coils whereby tuning adjustments may be made very quickly and easily and with a high degree of accuracy.

A further object resides in the provision of means whereby the coils and their cooperating parts can be quickly removed from their mountings when they are to be repaired or replaced by coils of a different number of turns to accommodate higher or lower frequencies.

The invention isillustrated in the drawings, of which Figure 1 is a horizontal section through the device;

Figure 2 is a vertical section taken on the line 2-2 of Figure 1;

Figure 3 is part of a front elevation of the device;

Figure 4 is the device;

Figure 5 isan end elevation of the device;

Figures 6 and 6 show details of contacts for tickler or primary coils;

Figures 7 and 7 a show details of a snaplock for the slit cover.

The form of the invention shown in the drawings is a preferred form, although it is understood that modifications in the construction and arrangement of the parts and in the character of the materialsused may be adopted without departing from the spiritof the invention as set forth in the appended claims.

In its general aspect the invention comprises a casing within which is mounted a rotatable form of insulating material on which a coil of wire or metal tape is wound. This form is mounted on a shaft or two stub shafts, which may be rotated from without the casing. Within the casing are disposed contact arms which are manipulated from without the casing and are supported on suitable rods, and to be slidable along the form to make contact with the wire or tape thereon. These contacts are mounted on slidable carriages which also have mounted on them guide arms which are grooved to lit the wire part of a rear elevation of or tape and adapted to guide the contacts along the wire or tape when the form is 1'0 tated but the guides may be lifted ofi the wire- (or tape, as the case may be) by manipulation from without the casing, and the contact then remains stationary or may be shifted across the turns of the coil without missing contact to the coil and the guide may then be put in operation on any turn desired.

A further feature is the fact that a cylindrical form carrying a coil and associated parts has its shafts lying in the bottom of slots in the casing so that they may belifted right out of the casing without any particular trouble, if they have to be repaired or replaced.

A further feature, when a cylindrical form is used, are auxiliary coils mounted within the main drum, or form, having longitudinal slides on their outer sides which slide in run.- ways secured longitudinally to the inner surface of the main drum so that the auxiliary coils may be slid longitudinally for adjust- 7 ment with regard to the main coil.

Furthermore, there are spring contacts which may be moved across the bared wire of the auxiliary coils by means of threaded rods which carry the carriages to which the contacts are secured thus making it possible to select the number of turnsused of the auxiliary coils. These contacts connect the auxiliary coils in the B battery and plate circuit or in the aerial and ground circuit by means of intermediate parts such as the carriage, the threaded rods and their bearings, spaced or isolated turns of wire on the main drum, spring contacts bearing on, these turns of wire and binding posts holding the spring contacts last mentioned.

The invention also resides in certain other features which will be hereinafter disclosed.

When a cylindrical form, or drum, is used to illustrate the invention, the preferred form of the invention, shown in the drawings, comprises a casing 10 having a cover 11 and in front of the casing is disposed apanel board 12. Mounted within the casing is a cylindrical drum, or form, 16, of insulating material supported by brackets 14 and 15 at each end of the drum or form. Attheir centers the brackets 14 and 15 are secured to one end of stub-shafts 13 and 13" which are in line with the axis of the drum and are supported in boxings 18 and 18 at the bottom of perpendicular slots 19 and 20 in the ends of the casing and are provided with collars to keep them from moving endwise and at the ends extending outside of the casing they are provided with knobs 21 and 22 as well as pointers 23 and 24 to point out the fractions of the turns on the annular shaped scales 25 and 26 which are removably secured to the ends of the cars ing by means of screws or snap locks. On the drum 16 is wound a length of wire 17 in the form of a coil. One end of the wire may be connected to a spaced turn 27 of wire by means of contact plate 28. The spring finger 29 bears against turn 27 and is connected to binding post 30. This binding postis slidable within a longitudinal slot 31 in the back of the casing. The other end of the wire may be similarly connected to a similar spaced turn of wire which is not shown in the drawings.

There are two other spaced turns of wire 32 and 33 on which spring fingers 34 and 35 are bearing and they are connected to binding posts 36 and 37, one of which may serve as a connection to the B battery lead and the other may serve as a connection to the plate lead. The turns 32 and 33 serve as connection links to one of the auxiliary coils as will be further explained. There are two more spaced turns of wire shown at the other end of the drum 38 and 39 on which spring fingers 40 and 41 are bearing and which are connected to binding posts 42 and 43 of which one may serve as connection to the aerial lead and the other may serve as connection to the ground lead. The binding posts 30, 42 and 43 are positioned in a longitudinal slot in the rear, or back of the casing so that they may be moved to any turn of the coil. Binding posts 36 and 37 are preferably stationary.

Disposed within the drum 16 is an auxiliary coil 45 mounted on drum 44 which has slides 46 and 47 attached longitudinally on the outer surface of 44 and spanning over and outside of 45 and they are adapted to slide in runways 48 and 49 which are attached longitudinally to the inner surface of drum 16 so that by means of the threaded rods 50 and 51 the drum 44 may be moved for adjustment with relation to the main coil. The rods 50 and 51 have suitable bearings which are attached to bracket 14 and operate drum 44 by means of threaded portions 54 which are attached to the inner surface of drum 44. The threaded rods 55 and 56 have suitable bearings 57 and 58 which are attached to the drum 16 and they each have a carriage 59 which is moved longitudinally when the rods are rotated. A spring contact finger 60 is secured to carriage 59 and bears against coil 45 so that when rods 55 and 56 are rotated the spring finger 60 passes across the turns of coil 45, making contact to any turn desired thus regulating the number of turns in active use. Bearing 57 is electrically connected to spaced turn 32 and bearing 58 is similarly connected to spaced turn 33 and these hearings are electrically connected to spring fingers 60. On their outer ends 50, 51, 55 and 56 have knobs to facilitate operation.

It will be noted in Figures 1, 2 and 5 that the shafts 13= and 13 lie in the bottom of slots 19 and 20 formed in the ends of casing 10 so that just removing scales 25 and 26 the main coil with the auxiliary coils with their asso ciated parts may be simply lifted out of the casing for repair or replacement.

Noting Figures 1 and 2 particularly it will be observed that I have provided two longitudinally extending shafts 61 and 62 dis posed parallel to the axis of the drum 16 at different levels between the drum 16 and panel 12. On opposite ends of shaft 61 are binding posts 63 and 64 and on opposite ends of shaft 62 are binding posts 65 and 66. Mounted, one on each of these shafts 61 and 62, are two sleeves such as 67 and 68 which are slidable along the shafts. Supported on these sleeves are fiat spring contacts 69 and 70 which are wide enough to span the distance between the centers of two adjoining turns of wire. Secured to sleeve 67 is a guide arm 71 and secured to sleeve 68 is a guide arm 72. At their lower ends these guide arms are grooved to fit the wire of coil 17 and are thus adapted to straddle and ride on the wire when the coil is rotated and consequently guide the contacts 69 and 70 along the wire from end to end of the same. The guide arms and their respective contacts are shown in the drawings to engage the same turn of the wire, but that notwithstanding, they may engage different turns. The upper end of guide arm 71 is adjustably secured to one end of rod 73 which is connected to rod 74 by means of coupling 75 and rod 74 passes outside through a horizontal slot 76 (Figures 2 and 3) in the casing 10 and the front panel 12 and the outer end is provided with knob 77 and pointer 78. After the angle between 71 and 73 is properly adjusted the joint is screwed tight so that 71 and 73 form one rigid unit and. after the proper distance of knob 77 from the panel 12 has been adjusted, a setscrew in coupling 75 is tightened to retain the adjustment. Guide arm 72 is similarly connected to red 79 which is connected to rod 60 by means of coupling 81, and 80 carries knob 82 and pointer 83 after it passes out through slot 84. The weight of these last mentioned parts as well as the pressure of the spring contacts 69 and 70 tend to hold the lower ends of guide arms 71 and 72 against the wire on the drum 16.

If it is desired to move spring contacts 69 and 70 across the turns of the coil 17 to a new position withoutthe necessity of revolving the drum 16 then the knobs 77 and 82 are lifted up'so that the lower-ends of guide-arms 71 and 72 are removed from the wire and lose their gripon thesamewhen the spring contacts 69 and 70 may be slid acrossthe wire to any turn desired without'missing contact to the wirew hile being moved. If'it is desired that the-spring contacts 69 and 'TOautomatically slide along the wire when the drum 16 is rotated, then the knobs 77 and 82 are allowed tofall' down until thelower ends of guide arms 71 and 72 straddle and press against the wire of coil 17..

On'the other hand, if it is desired that the spring contacts 69 or 70 remain stationary while the drum 16 is rotated, then the knob 7 Tor 82, as the case may be, is kept lifted up by means ofcover'plates 85 or 86 or, the one of them that is concerned, as shown in Figures 1, 2,. 3"and 5 where'knob 82 is'shown in anuplifted 'position' and kept' so by cover plate 86.

The cover-plate'85 is adapted to cover slot 7 6 and cover plate 86 is adapted to cover slot 84 when the device is not in use. Cover plates 85 and 86 are identical so that when one is described, this description applies to the other as-well'. Coverplate 85 is shown open and 86- is shown partly closed and pressing against the rod on which knob 82 is located. To befully closed the'rod 80'is moved to an aperture 87in the coverplate 86 in which rod 80 falls and is then not hindering the closing ofthe cover plate. There is a similar aperture in cover plate for rod 7 4. At each end of the cover plates are hangers 88 pivotally connected by pivots 89 which areprovided with knobs 90 and 91 at the lower ends of the hangers and the other ends are secured to shafts 92 which pass through a sleeve 93 to the inside of casing 10 where they carry snap arms 94 which engagethe free end ofsprings 95. the other end being held in clamps 96 which are secured 'to the casing 10. These parts are shown in Figure'7 and they form a snap lock with a tendency to keep the cover plates either open or: shut and the stops 97 may be adjusted to terminate the movements at the proper places.

The condenser 98 shown in Figures 1 and 2 is only for the purpose of illustrating my ideas for, the coil may be used in combina tion with any'kind of condenser, or it may be used without any condenser at all if condens ers are not required as blocking condensers.

My invention maybe incorporated in any circuit and if properly shielded more than one may be employed in the same circuit. If the coil does not contain the proper number of turns for a desired frequency it may be replaced by 'coils with more or less turns to suit the waveband desired and it may be used in combinaton with a loading coil.

Atthis point it is desirable to call attention tov the fact that coilsmay be wound with tape instead of wire and when wire-is mentioned it is intended to include-metal tape.

When my invention of a rotatable coil having contacts that slide on the wire of the coil so that contact maybe made, automatically or manually, to any place on the wire, is applied to coils of different construction there must of necessity be some variation in the mechanical means employed.

As before stated, the device maybe used to advantage in any circuits and maybeused singly or in any number desired, on separate shafts with dials or they may be mechanically connected so as to operate all by means of one control if they are properly shielded one from the others.

We therefore have a rotatable coilwound on any suitable form with sliding contacts which may either be slid manually across the turns of the coil or automatically slid: along the wire of the coil by means of a guide when the coil is rotated for adjustment and we also have a plurality of coils which can be longitudinally adjusted with respectto the main coil as well as being adjustable with regard to the number of turns of wire in effective use. All the coils are easily removed and may be replaced by other coils ofmoreor less turns to suit the frequency of the desired signals without disarranging the other parts.

lVhat I claim is: 1. A tuning coil which comprises a rotatable form, a coil of wire mounted thereonin a spiral fashion, aslidable contact finger bearing on the wire, suitable support for the contact finger, means whereby rotation of the form will cause an automatic continuous and unbroken sliding contact of the finger with and along the wire as well as an automatic sliding motion of the contact finger along its support in a straight line across theturns of the coil, and means for manually sliding the contact finger on its support in a straight line across the turns of the coil in contact with the coil.

2. In combinatioma rotatable coil of wire, a form on which said coil is mounted, a contact finger bearing against the wire, a guide arm attached to said contact finger and constructed to partially embrace the wire, a support for said contact finger and guide arm, means permitting the slidable movement of thefinger and guide along the support and means for manually moving the guide arm away from the wire at will independent of the position of the support and without releasing the contact finger from contact with the wire of the coil. I

3. In combination, a coil form, a coil of wire spirally wound thereon or attached thereto, a rod disposed alongside said form and in a direction across the turns of said coil, a slidable carriage mounted on the rod, a contact finger mounted on the carriage and bearing against the wire, a guidearm 1 lot) mounted on the carriage, said guide arm constructed to partially embrace the wire, and a lever connected to the carriage and to the guide arm permitting the manual retraction of the guide arm from the wire at will and without releasing contact finger from contact with the wire.

4. In combination, a cylindrical form, a coil of wire wound spirally thereon, brackets at tached to and across the ends of the form, shafts attached to these brackets mounted for rotation of the coil, channel sha Jed runways mounted longitudinally on the inner face of said form, a second cylindrical form, a second coil spirally wound on the second form, slides attached longitudinally to the outer face of said second form and coil and adapted to slide in said runway within the first mentioned form, a rod partly threaded and adapted for movement of the second form inside the first mentioned form, threaded carriages mounted on the threaded part of said rods and secured to the second form, another partly threaded rod adapted to move a carriage across the turns of the second coil, a threaded carriage mounted on the threaded part of the last mentioned rod, and a contact finger attached to the last mentioned carriage and adapted to bear against the wire of the second coil.

5. In combination, a casing, a slot therein, a panel in front of said casing having a slot that coincides with the slot in the casing, a cover plate for said slot, hangers pivotally attached to the cover plates, shafts on which the hangers are mounted passing to the inside of the casing, cams mounted on the inner end of the shafts, springs engaging the cams comprising a snap lock adapted to keep the cover plates open or shut and means to open or shut the cover plates at will.

6. In combination, a rotatable coil, a drum on which said coil is mounted, a channel shaped runway attached longitudinally to the inner face of said drum, an auxiliary coil having slides adapted to slide in said runways within the first mentioned drum, threaded rods adapted to move the auxiliary coil longitudinally with reference to the first mentioned coil, a threaded rod, a carriage on the last mentioned rod, and a contact mounted on the carriage that is hearing against the wire of the auxiliary coil and is adapted to move across the turns of said auxiliary coil.

7. In combination, a rotatable coil, a form on which said coil is mounted, a contact-finger bearing against the coil, a guide-arm attached to said contact-finger and constructed to partially embrace the coil, support'for said contact-finger and guide-arm, means permitting the slidable movement of the finger and guide arm along the support, means for manually moving the guide-arm away from the coil at will and independent of its position on the support and without removing the contact-finger from contact with the coil, and suitable means for mounting the form as well as the support of the contact-finger and its guide-arm.

8. In combination, a coil-form, means to rotatably mount said form, a coil of wire spirally mounted on said form, a plurality of contact-rings or spaced turns mounted on the form, a plurality of contacts bearing against said spaced turns or rings, means to movably mount and support said contacts, a rod disposed alongside said form in a direction across the turns of the coil, means for suitably mounting said rod, a slidable carriage mounted on the rod, a contact-finger mounted on the carriage and bearing against the coil, a guide-arm mounted on the carriage and constructed to partially embrace the coil, and a lever connected to the carriage and the guide-arm permitting the manual retraction of the guide-arm from the coil at will and without removing the contact-finger from the coil.

9. In combination, a helical coil of conducting material, a rotatable form on which said coil is mounted, a slidable carriage, a support for the carriage adapted to allow the carriage to slide across the turns of the coil in a straight line independent of the rotation of the form and coil, a contact finger adjustably mounted on the carriage and bearing against the turns of the coil, means whereby rotation of the form will cause the finger to make continuous sliding contact with and along the turns of the coil independent of the pitch of the winding and at the same time cause the carriage to slide on its support in a straight line across the turns of the coil.

10. In combination, a helical coil of conducting material, a rotatable form on which said coil is mounted, shafting attached to the form for mounting the latter, a plurality of contact rings mounted on said form, a plurality of contacts bearing on the rings, a rod alongside the coil in a direction across the turns of the coil, a carriage slidingly mounted on the rod, a contact finger attached to the car riage and bearing against the coil, a guide arm attached to the carriage, a lever attached to the carriage and to the guide arm, means for rotatable and removable mounting of the form, means for suitable mounting of the contacts bearing on the contact rings, means for indicating fractions of one revolution of the form, and means for indicating the number of turns of the coil in actual use.

11. In combination, a rotatable form of dielectric material, a coil of conducting material'mounted on. the form in a spiral fashion, runways attached longitudinally to the inner face of the form, an auxiliary coil inside the main coil and in inductive relation to the same, slides attached to the outer face of the auxiliary coil and adapted to slide in the run- Ways mentioned, and a rod adapted for sliding the auxiliary coil longitudinally for adjustment of inductance between the auxiliary coil and the main coil.

12. In combination, a rotatable form of dielectric material, a coil of conducting material mounted in a spiral fashion on said form,

runways attached longitudinally to the inner face of the form mentioned, an auxiliary coil adjustably mounted inside the main coil, slides attached to the outer face of the auxiliary coil and adapted to slide in the run Ways mentioned for longitudinal adjustment with relation to the main coil, a plurality of partly threaded rods, boxings secured to the main form, threaded carriages on the threaded rods having contacts adapted to move across the turns of the auxiliary coil and being in contact With the same on the outer face of the auxiliary coil, and means to slide the auxiliary coil for adjustment With relation to the main coil.

ROBERT JULIUS JOHANSSON STARR. 

